1. Field of the Invention
The present invention relates to an ethylamine derivative, which exhibits antihypertensive properties.
2. Description of the Background
It is said that there are about 13,000,000 hypertension patients in Japan, and the frequency of hypertension is higher with advancement in age. In addition, the condition of hypertension is an important factor in cerebral apoplexy and cardiopathy which are the second and third highest causes of death, respectively. Accordingly, antihypertensive drugs are one of the most important classes of drugs in the treatment of gereatric diseases.
About 90% or more of hypertensive patients are believed to suffer from essential hypertension, the cause of which is not clear, and the remedy therefore is merely within the range of an expectant treatment for the disease. Accordingly, patients are required to continuously take an antihypertensive drug all of their lives, and so the antihypertensive drug should have high safety and a sure pharmaceutical activity against hypertensive and further must be durable.
Recently, the serotonin-antagonistic antihypertensives have been reported. However, these compounds are not always satisfactory from the viewpoint of their antihypertensive mechanism, as well as their durability. In addition, serotonin-antagonistic drugs have been reported to be effective against various diseases caused by serotonin, for example, thrombosis, ulcers and the like, but the effect of such drugs against such diseases is not so clear. On the other hand, from the viewpoint of the preparation of the said antihypertensives, not an insignificant number of compounds and synthetic intermediates for the antihypertensives are difficultly soluble in organic solvents or are produced by procedures which are complicated and troublesome. A need therefore continues to exist for antihypertensive drugs which can be conveniently prepared at low cost and which have excellent overall effective properties.